The groundbreaking technology of bioprinting is showing promise in building scaffolds in which to grow cells for regenerative medicine applications.

The study’s findings were published in the November 2012 issue of the journal Science. In the article, Prof. Brian, from the University of Manchester’s (UK) School of Materials assessed the hypothesis of employing printer technology to construct structures in which to grow cells, to help to regenerate tissue.

Both laser printer and inkjet technology can be used to build the three-dimensional (3D) scaffolds that cells can be grown in and also position the cells in these structures simultaneously. Prof. Derby clarified how bioprinting works, “Inkjet technology places the structure’s material in small droplets, which then solidify. More droplets are then placed on top of the previous ones in a specific pattern. The structure is built using this method that is generally referred to as additive manufacture. Laser printing uses light to solidify the structure’s substance layer upon layer. These methods have allowed us to develop very complex scaffolds which better mimic the conditions inside the body.”

The scaffold provides a surface for the cells to adhere, multiply, and flourish. Both the scaffold substance, composition, and its internal structure regulate the behavior and health of the cells inside. In his review article, Prof. Derby examined research where porous structures have been constructed through bioprinting. They are then positioned in the body to help act as a scaffold to encourage cell growth. The cells colonize the structure and it either dissolves or becomes part of the body. This type of treatment can help patients suffering from ailments such as cavity wounds. Clinical trials are ongoing worldwide to refine this technology, and according to Prof. Derby, it is moving towards becoming an established form of science.

Prof. Derby also studied how stem cells are being grown in printed structures that have been permeated with specific chemicals. The chemicals are inserted during the printing process and can determine the type of cell into which the stem cells develop. Stem cells, for instance, could be programmed to become cells that comprise cartilage or bone tissue.

However, there are drawbacks to the technology that is holding back advances such as the capability to grow a complete organ. Study findings have revealed that it is very challenging to actually print the cells at the same time as making the structure that will hold them. The stress on the cell as it goes through both the inkjet and laser process can injure the cell membrane. Cell survival rates have also been variable, ranging from between 40%-95%.

The technology is also a ways from being a research platform to clinical practice. Whereas scaffolds are being clinically trialed, essentially transplanting cells grown in an external structure into a patient is a more sophisticated process. It is still not possible at present to assure a consistent quality, which is required by medical device regulations.

However, studies are being conducted to grow external cells into tissue, such as a skin patch, and transplant that into a patient. Prof. Derby is currently working with ear, nose, and throat surgeons at the Manchester Royal Infirmary. He wants to use bioprinting to print cells without using a scaffold. The printed cells form a sheet that can be used for grafts inside the body, for example, in the nose or mouth.

Prof. Derby said, “It is very difficult to transplant even a small patch of tissue to repair the inside of the nose or mouth. Current practice, to transplant the patient’s skin to these areas, is regarded as unsatisfactory because the transplants do not possess mucous generating cells or salivary glands. We are working on techniques to print sheets of cells that are suitable for implantation in the mouth and nose.”

An area that Prof. Derby foresees is the ability to grow structures that can mimic cancerous tumors. These could then be used to evaluate new drugs, which it is hoped will further the search for more effective treatments. Prof. Derby concluded that there is a strong future for bioprinting and while growing organs is still quite a ways off, these recent developments are very encouraging.